In a tab panel with deferredRender set to false, toolbars on the tab item render correctly, but nested toolbars are not correctly rendering combobox controls. They appear stacked on top of one another. LayoutOnTabChange set to true does not correct it.

The only way I was able to correct it manually from firebug was to call .syncSize() on each combobox, (which set the width very small), then call .setWidth(120) on each combobox. I have not found a way to correct it in code, other than to set deferredRender: true